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Delineation Toolbox

Tools, Forms, Guidance, and Links for Wetland Delineators

This page contains technical information useful for wetland delineations and assessments.

Delineation Methods: Approved for Washington State

Delineation Data Forms: 

WSDOT uses the following customized fill-in data forms:

WSDOT Delineation Guidance


Other Guidance for Washington


Vegetation Tools

WSDOT follows the plant naming conventions as updated by the National Wetland Plant List.

  • For plants commonly found in Washington, WSDOT uses simple codes instead of the full scientific name to record field data.  A plant code list (pdf 290 kb) (WSDOT 2014) provides the scientific and common names, origin, and the indicator status of a subset of commonly encountered plants based on the NWPL (Version 3.2).   
  • WSDOT developed a corresponding auto-text macro for Microsoft Word (WSDOT 2014) that inserts the same information from the plant codes. Installation instructions, the plant codes and the macro file “Autotext_Plants.dotm” can be obtained from the public FTP server (or the WSDOT internal FTP server).     


Soil Tools

To describe soils, use the most recent version of these USDA NRCS publications:

  • Field Indicators of Hydric Soils in the United States
  • Soil Surveys Online USDA-NRCS web page 
  • National Hydric Soils Lists  
  • Official Soil Series Descriptions  
  • Field Book for Sampling and Describing Soils 
  • NRCS Washington state  web page


Hydrology Tools

  • The Regional Supplements recommend using the methods described in Chapter 19  of the USDA NRCS Part 650 Engineering Field Handbook to determine if antecedent precipitation is within the normal range. 
  • WSDOT’s process  for writing the Wetland Hydrology section (pdf 1060 kb) of a Wetland and Stream Report is based on Chapter 19 of the USDA NRCS Part 650 Engineering Field Handbook.
  • WSDOT installs shallow groundwater monitoring wells in accordance with the guidance available in the Wetlands Regulatory Assistance Program Technical Notes, US Army Corps of Engineers:

Noble C. 2006. Water Table Monitoring Project Design.  Vicksburg (MS): US Army Engineer Research and Development Center. (pdf 7.4 mb)

US Army Corps of Engineers. 2005. Technical Standard for Water-Table Monitoring of Potential Wetland Sites. Vicksburg (MS): US Army Engineer Research and Development Center. (pdf 1.5 mb)

Sprecher SW. 2000. Installing Monitoring Wells/Piezometers in Wetlands. Vicksburg (MS): US Army Engineer Research and Development Center. (pdf 1.5 mb)


Washington Wetland Rating Systems: Washington State Department of Ecology

Use Ecology’s most recent version of the Washington State Rating System appropriate for the project.

 Rating Data Forms:

Use WSDOT’s forms to rate wetlands impacted by the project. WSDOT adapted these forms into a Microsoft Excel 2010 format for use in Windows 7. Others may use the forms, however, WSDOT does not guarantee they will work with other computers and software, and will not provide support if they do not.

Classification Methods 

To classify wetlands, use the most recent version of these publications:

  • Classification of Wetlands and Deepwater Habitats of the United States (Federal Geographic Data Committee 2013) adapted from Cowardin et al. 1979.
  • Classification of Wetlands and Deepwater Habitats of the United States (Cowardin et al. 1979).
  • National Wetland Inventory
  • Hydrogeomorphic Classification for Wetlands 


Functions Characterization/Assessment

Optional methods to evaluate functions. Other methods may also be appropriate for use.

Wetland and Buffer Impact Calculation

The WSDOT Wetland and Buffer Impact Assessment Guidance (pdf 465 kb) describes the process WSDOT uses to determine wetland and buffer impacts. This guidance provides a process and checklist for impact assessment.

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